The present invention relates to a method for preheating the oxygen in oxygen steel making processes, especially in the so called LD-Process.
In oxygen steel making processes, the entire energy required for the metallurgical reactions is usually supplied exclusively by the heat of reaction. Therefore the amount of material which can be charged solidly is limited. In an LD converter, up to about 30% of the total charge can be charged as cold scrap iron.
However, there are situations, particularly of an economic nature, which call for a higher cold scrap percentage, especially in the LD-steel process. A scrap iron preheating has been proposed, either in the converter or before charging. However, these known methodes to increase the use of cold scrap are unsatisfactory. The preheating in the converter itself reduces the output. In the preheating outside the converter, considerable heat losses by radiation must be accepted; in addition, the operation is made less efficient.
It has also been proposed that in converter operation, the blowing air be preheating by using the heat given off by the converter waste gases (German Pat. No. 824,791); however, the manner suggested, the preheating of the air in heat exchangers or heat storages receiving waste gas, is found economically impractical in view of the high load of dust and slag particles in the discharged waste gas.
It is therefore, an object of the present invention to preheat the oxygen, in an practical and economic manner. Instead of pure oxygen wind or oxygen enriched wind may be used too.
Another object of the present invention is to provide an heating arrangement of the foregoing character which may be readily maintained in service and which requires no unusual operator skill or operating procedures.
A further object of the present invention is to provide an arrangement, as described, which does not reduce the service life of the preheating installations.